On March 8, local time, at the Third International Summit of Human Genome Editing held in London, England, Katsuhiko Hayashi, a professor from Kyushu University in Japan, introduced the details of this study and said that he had submitted it to the scientific magazine Nature.

This technology first extracts skin cells from male mice and then transforms them into a state similar to stem cells to create so-called induced pluripotent stem cells (iPS cells)-cells that can be transformed into other types of cells. Because skin cells are extracted from male mice, they have XY chromosomes. Professor Lin Keyan's team removed the Y chromosome, "borrowed" an X chromosome from another cell, and then skillfully "glued" the two X chromosomes together. This process turns stem cells into eggs.

"The biggest trick is to copy the X chromosome," said Professor Lin Keyan. These cells with two X chromosomes are cultured in an ovarian organ to form eggs. When fertilized with normal sperm, scientists obtained about 600 embryos and implanted them into surrogate mice. In the end, the surrogate mouse gave birth to seven pups.

These mice look healthy, have a normal life span, and can continue to reproduce as adults. "They are good-looking, grow normally and can be fathers in the future." Professor Lin Keyan said. In the experiment, the success rate of about 1% is lower than the 5% success rate that normal female eggs can achieve.

New hope for infertile patients?

At this stage, this technology can not be safely used for human beings.

Professor Lin Keyan said that the main motivation of this study is to provide a fertility treatment for couples with infertility, such as women with Turner syndrome, whose replicated X chromosome is completely or partially missing.

He went on to add that the research is still in the early stage and the quality of egg cells is not high. "Even in mice, there are many problems with the quality of egg cells. Therefore, we must overcome these problems before we can consider it as a fertility treatment method, which may take a long time. " He said.

At the same time, at present, technology can not be safely used by human beings. However, he believes that this problem will be solved in 10. However, some scientists think that this time estimate is too optimistic, because no viable human egg cells have been created from female cells under laboratory conditions. In addition, some scientists suggest that human cells need longer culture time to produce a mature egg cell, which may increase the risk of unnecessary genetic changes.